Room Acoustics

The Effects of Room Acoustics

Any given room will have natural reverberation and ambient noise. There are many instances where these elements need to be accounted for. Whether it be a recording studio or any larger area such as a church that has a PA system, reverberation time and ambient noise level are essential to account for. In a recording studio, room acoustics are obviously vital as the natural reverberation and ambient noise directly affect the sounds that you are recording. In a large area with a PA system, the room acoustics should always be accounted for because they have a large impact on speech intelligibility.

RT60 Reverberation Time

The reverberation time (or RT60) is among the most commonly specified room acoustics measurements. Unfortunately, reverberation time measurements are also among the most complex to carry out accurately. Standardized procedures for measuring the reverberation time of a room are specified in ISO-3382-2. Generally speaking, there are two different ways to measure RT60: the impulse response method and the interrupted noise method. Both methods are standardized through ISO-3382-2. The interrupted noise method, as supported by the Bedrock SMxx, measures the decay of the sound field if a sound source is suddenly switched off. This method is more robust against slight inaccuracies or inconsistencies in the placement of sound source and microphone.

Noise Curves

The noise curves module implements a series of measurement methods to evaluate noise levels, based on sets of standardized spectral curves. The objective of these methods is to set criteria in terms of a single-number rating, while taking the spectral characteristics of noise into account. The Bedrock SMxx devices are capable of using several methods to test noise curves. The Noise Criteria (NC) method is frequently used in the United States, mostly for evaluating background sound in buildings and for specification of desired levels in advance of construction. Different versions of the NC have been in circulation since the 1950s; the SMxx implements the version standardized through ANSI S12.2:2008.